The regeneration of bone that is capable of growth during the point of care in a hospital room is critical for a successful bone graft surgery. Approximately 83% of bone grafting uses autogenous grafts and 17% involve artificial substitutes. The medical technologies for the three elements of in-situ tissue engineering has proven to be predictably effective and safe. Here’s how medical technologies are combined to create a viable bone matrix for predictable bone regeneration.
Mesenchymal Stem Cells are first obtained using one of two technologies. The first technology is known as the Harvest Technologies System. It aspirates around 60 ml of autologous bone marrow from the posterior or anterior ilium. The aspirate is added to a transfer bag that contains four ml of ACDA anticoagulant. Then 60 ml of this mixture is transferred from the bag into a canister containing a floating shelf that separates osteoprogenitor cells from the bone marrow plasma.
The second technology is known as the Lenkbaar Marrow Marxman. It also aspirates bone marrow but has the capability of penetrating cortical surfaces where more mesenchymal stem cells reside. Only 10 ml of this material is needed.
Recombinant human Bone Morphogenetic Protein-2 (BMP-2) is known to be the signal for bone regeneration. It’s a protein that’s coded from chromosome 20 and separated from it by using restricted fragment enzymes. These enzymes are then attached to a plasmid, which is a bacterial extranuclear DNA ring. The injected plasmid is introduced into a Chinese Hamster Ovarian cell that produces a large amount of BMP-2 as well as hamster proteins.
Nanofiltration and electrophoresis are used to separate the human BMP-2, which is then freeze-dried for clinical use into a white crystallized powder. Before use, a dose of the freeze-dried crystals is placed in a pre-set package of sterile water. It’s then placed onto an acellular bovine collagen sponge for 15 minutes.
The viable bone matrix is derived from the stem cell plasma component which contains various cell adhesion molecules that will act as a scaffold where the unmineralized organic component of bone can be deposited. Freeze-dried cancellous allogeneic bone is also used to build the matrix for the in-situ bone tissue engineering.
During the bone repair surgery, the matrix is clotted with a mixture of calcium chloride into either recombinant human thrombin or lyophilized bovine thrombin. This clotting causes cell adhesion molecules to bind to the allogeneic bone surface and release various growth factors. A sponge that is wetted with this mixture is cut up by the surgeon into small squares. This is done to help create a space so that functional bone can fully grow, remodel, and fuse to be able to host bone for dental implants in the jaw.
In-situ bone tissue engineering is predictable for creating a viable bone matrix due to its sound wound healing and embryologic principles. The simplicity and safety are beneficial for both the surgeon and the healthcare system as a whole. Not only does it reduce operating and hospitalization time for graft delivery, but it also reduces the amount of pain and post-operative care for the patient.